Safety device for neutralizing the clutch of a snowmobile

ABSTRACT

Device for neutralizing, when starting up, the driving effect of a pulley having truncated cheeks of which a first one is secured on a rotary axle whereas a second one is slidably mounted thereon, the cheeks being biassed by a spring tending to move the second cheek from the first one, this movement being however subjected to the counter-effect of a governor mounted on the axle to rotate therewith and of which the centrifugal masses act on the second cheek to bring it back toward the first one as soon as the axle is brought into rotation beyond a predetermined speed. This device comprises a locking mechanism mounted on the axle to cooperate with the second cheek in such a manner as to prevent it, as soon as the axle starts rotating, from moving toward the first cheek under the action of the centrifugal masses. It also comprises a manually operable mechanism related to the said locking mechanism in such a way as to release, when operated, the second cheek so that it may suddenly be projected toward the first cheek when the axle is placed in rotation at a speed greater than the said predetermined speed. This locking mechanism comprises a collar solid with the second cheek and two levers pivotally mounted at one end on the axle so that their other end may move away from the axle under the effect of the centrifugal force. The collar and the levers are made so that the said other end of the levers may come in abutment against the collar when the axle starts rotating and thus hold it; the manually operable mechanism comprises means capable of holding the levers in abutment position, this means being displaceable at will to release the levers once the axle has reached the aforesaid predetermined speed.

United States Patent 1 Belanger et al.

[111 3,750,486 5] Aug. 7, 1973 SAFETY DEVICE FOR NEUTRALIZING THE CLUTCHOF A SNOWMOBILE [76] Inventors: Regis Belanger, St-lsidore, Quebec;

Edouard Belanger, St-David, Quebec, both of Canada [22] Filed: Dec. 9,1971 [21] Appl. No.: 206,423

[30] Foreign Application Priority Data July 2, 1971 Canada 117,290

[52] US. Cl. 74/230.l7 E, 192/105 C [51] Int. Cl. Fl6h 55/52 [58] Fieldof Search 74/230.l7 E; 192/105 C, 89 W, 114

[56] References Cited UNITED STATES PATENTS 3,362,242 1/1968 Watkins74/230.17 E 3,675,500 7/1972 Albertson 74/230.17 E FOREIGN PATENTS ORAPPLICATIONS 96,066 2/1957 Germany 192/105 C Primary Examiner-Charles J.Myhre Assistant ExaminerR. l-l. Lazarus Attorney-Raymond A. Robic 57ABSTRACT Device for neutralizing, when starting up, the driving effectof a pulley having truncated cheeks of which a first one is secured on arotary axle whereas a second one is slidably mounted thereon, the cheeksbeing biassed by a spring tending to move the second check from thefirst one, this movement being however subjected to the counter-effectof a governor mounted on the axle to rotate therewith and of which thecentrifugal masses act on the second cheek to bring it back toward thefirst one as soon as the axle is brought into rotation beyond apredetermined speed. This device comprises a locking mechanism mountedon the axle to cooperate with the second cheek in such a manner as toprevent it, as soon as the axle starts rotating, from moving toward thefirst check under the action of the centrifugal masses. It alsocomprises a manually operable mechanism related to the said lockingmechanism in such a way as to release, when operated, the second cheekso that it may suddenly be projected toward the first cheek when theaxle is placed in rotation at a speed greater than the saidpredetermined speed. This locking mechanism comprises a collar solidwith the second cheek and two levers pivotally mounted at one end on theaxle so that their other end may move away from the axle under theeffect of the centrifugal force. The collar and the levers are made sothat the said other end of the levers may come in abutment against thecollar when the axle starts rotating and thus hold it; the manuallyoperable mechanism comprises means capable of holding the levers inabutment position, this means being displaceable at will to release thelevers once the axle has reached the aforesaid predetermined speed.

5 Claims, 6 Drawing Figures SAFETY DEVICE FOR NEUTRALIZING THE CLUTCH OFA SNOWMOBILE The present invention relates to improvements in atransmission for a snowmobile, or the like vehicle, and moreparticularly to improvements to the pulley mounted on the driving axle.

This type of pulley has truncated cheeks of which a first one is securedon a rotary axle, generally the driving shaft, whereas a second cheek isslidably mounted thereon. The checks are subjected to the action of aspring tending to move the second cheek away from the first one, thismovement being however opposed by a governor mounted on the axle and ofwhich the centrifugal masses act on the second check to push it towardthe first one as soon as the axle is brought into rotation beyond apredetermined speed. At a lower speed, the belt lies at the bottom ofthe groove of the pulley and is inactive, the pulley then idling.

In this type of mechanism, the belt starts to drive the track of thesnowmobile as soon as the speed of the axle rises beyond thepredetermined speed mentioned above. This situation does not usuallypresent any difficulies since there are generally no particular reasonsfor starting up very rapidly and allowing the snowmobile to reach itscruising speed in the shortest possibletime. In other words, there isusually no necessity for the snowmobile to have a high acceleration whenstarting up.

The situation is however quite different during competitions where timeis an essential element, as is the case during a race. Unfortunately,the usual snowmobiles do not have any device for fast start up and it isprecisely the object of the present invention to provide a mechanismthat will allow the snowmobile to reach, starting from rest or fromidling, its cruising or maximum speed in the shortest possible timeperiod, that is give it an acceleration which is considerably greaterthan that permissible with known transmissions.

For this purpose, we have conceived a device intended to neutralize,when starting up, the driving effect of the transmission pulley byholding, at will, the movable jaw of the pulley to thus allow the axleto reach a high speed, without driving the belt. When the startingsignal is given, the movable jaw is suddenly released and is, under theeffect of the centrifugal masses of the governor, projected with forcetoward the other jaw which is stationary in'translation. The belt isthen suddenly clamped with a force which is greater the higher the speedof the axle at that particular moment. The belt then moves very rapidlytoward the periphery of the pulley to take on the position thatcorresponds to the speed of the axle.

In accordance with the preferred embodiment of the invention, thelocking mechanism comprises a collar solid with the second cheek andprovided with at least one lever pivotally mounted at one of its ends onthe axle in such a way that its other end may move away from the axleunder the centrifugal force, the collar and the lever being soconstructed that the said other end of the lever comes in abutmentagainst the collar as soonas the axle starts rotating to thus hold thecollar back and keep the second cheek from moving in translatiori on theaxle. The manually operable mechanism comprises means capable of holdingthe lever in abutment position, such means being displaceable at will torelease the lever once the speed of the axle has gone beyond thepredetermined speed.

A better understanding of the invention will be afforded by thedescription that follows of a preferred embodiment thereof havingreference to the appended drawings wherein:

FIG. 1 is a perspective view, partially in crosssection, of a deviceapplying the improvements of the invention, the part shown in brokenline illustrating a conventional pulley;

FlG. 2 is a longitudinal cross-sectional view of the device of theinvention combined with a pulley of conventional type, the situationshown being that of the snowmobile starting up with the axle idling;

FIG. 3 is a cross-sectional view similar to that of FIG. 2 butillustrating the transmission with the axle having reached cruisingspeed;

FIG. 4 is an elevation view of the locking device with part of thepulley being shown in cross-section, and

FIGS. 5 and 6 are respectively cross-sectional views in planes extendingalong lines V--V and Vl--Vl of FIGS. 2 and 3.

Referring now more specifically to FIGS. 1, 2 and 3, the pulley improvedby the addition of the device of the present invention is of the typehaving two truncated cheeks 1 and 3 defining therebetween a groove 5 inwhich a belt 7 winds. The cheek 3 is secured over the driving shaft oraxle 9 for rotation therewith by means of a key- 11, in known manner. Onthe other hand, the check 1 is slidably mounted on the axle 9, beingsecured by means of screws 13 to a sleeve 15 slid on the axle 9 in sucha manner that it may freely move in translation thereon.

The sleeve 15 has an'axial central counterbore 17 in which there is aspiral spring 19 wound around the axle 9 and respectively bearingagainst a shoulder 21 at the bottom of the counterbore l7 and a ring 23resting by one end on the bottom of the cheek 3 and of which the outerdiameter allows it to freely enter counterbore l7. Mounted inside adome-shaped web 25 and secured to the axle 9 is a governor havingcentrifugal masses 27 pivoted, as at 29, on brackets 31 welded insidethe dome 25. The governor has four masses 27 of which only two areshown. Each mass 27 extends into a protuberance 33 having a rounded endhoused within a notch 35 provided on the outer face of the sleeve 15,the protuberance 33 hearing against a shoulder formed at the bottom ofits notch 35.

The spring 19 has a pushing force sufficiently great so that when theaxle 9 does not rotate or idles, at a speed within a predeterminedspeed, the belt 7 floats at the bottom of the groove 5 and is notdriven.

Beyond this predetermined speed, called the idling speed, thecentrifugal force developed by the masses 27, rotating about the pivots29, is sufficient to overcome the resistance of the spring 19 so thatthe protuberances 33 drive the sleeve 15 and thus the cheek 1 toward thecheek 3. The belt 7 is thus compressed or clamped and driven intorotation while moving up in the groove 5 a distance depending on thespeed of the axle.

The device and function described above are known and it does not appearuseful or necessary to elaborate further.

The improvement according to the invention resides, as explained above,in the combination with a device of the aforesaid type, of a lockingmechanism mounted on the axle 9 to cooperate with the second cheek l insuch a way as to prevent its movement toward the first check, movementthat it normally has under the effect of the centrifugal masses 27, assoon as the axle starts rotating, and of a manually operable mechanismcombined with the aforesaid locking mechanism in such a way as torelease, when actuated, the second cheek 1 to allow it to suddenly movetoward the first cheek 3 when the axle 9 is brought into rotation at aspeed which is beyond the aforementioned predetermined speed.

In the preferred form of the invention, the locking mechanism comprisesa ring-shaped collar 37 made solid with the sleeve 15, and thus with thecheek l, by means of elongated bolts 39 (FIG. 4) screwed at one end on aterminal face of sleeve 15 and secured at the other end on the collar 37by means of nuts 41. It will be noted, in FIGS. 2 and 3, that the innerface of the collar 37 is bevelled at 43. The mechanism also comprises atleast one lever 45, preferably two as illustrated, pivotally mounted at47 on the axle 9 or, more precisely, on a projection thereof in the formof a hollow cylinder 49 which is secured on the axle 9 by means ofa stud51 and ofa tenon 53, the latter being received in a correspondingmortise of the axle 9. This assembly makes the cylinder 49 solid withthe axle 9. The other end of the levers 45 is bent, toward the axle, inthe shape of latches 55 adapted each to be inserted into a correspondingopening of the cylinder 49, which openings act as keepers for thelatches 55. The said keepers have, like collar 37, a bevelled corner 57intended to bear against the bevel 43 of the collar 37. These bevelledsurfaces 43 and 57 are designed to facilitate reciprocal sliding actionof the levers 45 and of the collar 37, as will be explained hereinafter.The collar 37 has slots 58 (FIGS. and 6) for the passage of the latches55. The bevelled faces 43 are provided at the bottom of the said slots.As to the locking mechanism, it comprises a bearing 59 in the shape of aball bearing slidably mounted inside the chamber 61 of the cylinder 49and secured on the end of a tubular elbow 63 which has a vertical branchcapable of moving inside a U-shaped guide 65 securely mounted on theframe 67 of the machine. The bearing 59 is pushed outside the chamber 61by a spring 69 but it is prevented from moving out by a split ring 71(FIG. 5) fixed inside the chamber 61. The other end of the spring 69bears against another split ring 72 wedging a second bearing 73 that, inturn, bears against a shoulder 75 formed at the bottom of the chamber61. The manually operable mechanism also comprises a bowden cable 77 ofwhich one end is held by the second bearing 73 and the other end isfixed to a L-shaped control lever 79 (see FIG. 1), after having passedthrough the movable elbow 63 and the usual flexible tubular sheath 81 ofwhich one end is fixed to a bracket 83 while the other end is fixed tothe movable elbow 63. The bracket 83 as well as the control handle 85are fixed in relation to the axle 9 whereas the tubular elbow 63 ismovable.

The above-described device operates as follows:

When the axle 9 is stationary, the spring 19 pushes the sleeve leftward(FIG. 2) as well as the collar 37. If, at that moment, the levers 45 arein the position of FIG. 3 with the latches 55 pushed inside the chamber61, they will pivot outwardly under the effect of the centrifugal forceas soon as the axle 9 idles and before the centrifugal masses, having agreater inertia, may

have any effect. The device will then be in the position shown in FIG. 2with the latches 55in abutment against the collar 37 which will have theeffect of holding the sleeve 15 and the jaw 1. It will also be notedthat the spring 69 then pushes the bearing 59 under the latches 55 tohold the latches in abutting position. The belt 7 lies at the bottom ofthe groove 5 and is not driven. It is then possible to increase thespeed of the axle 9 at will and have it reach a desired speed withoutany danger of the belt 7 being driven since, as mentioned previously,the collar 37 is held captive by the latches 55 of the levers 45.

At the desired moment, that is when the starting signal of the race isgiven, the operator actuates the lever 79 counterclockwise thus pullingon the cable 77 but as the other end of the cable inside the chamber 61is fixed and at least because of the bend in the elbow 63, it is thelatter that moves inside the chamber 61 causing sliding motion of thebearing 59 against the action of the spring 69 and release of thelatches 55. At that moment, the centrifugal masses 27 cause slidingdisplacement of the sleeve 15 rightward, the collar 37 then sliding overthe levers 45 (see FIG. 3) because of the release of the latches 55 andunder the effect of the bevelled faces 43 and 57.

Obviously, the release ofthe sleeve 15 and thus of the check 1 takesplace very quickly so that it becomes possible to very suddenly apply tothe belt 7 a high speed, meaning a fast acceleration. Under thisimpulse, the belt moves rapidly toward the periphery of the groove andtakes on a position that obviously corresponds to the speed of the axle9.

When, eventually, the speed falls again to a value that brings the belt7 at the bottom of the groove 5 in inactive position, the spring 19brings the collar 37 back in the positionof FIG. 2 and the centrifugalforce causes the lever 45 to pivot outwardly in abutment against thecollar 37; the spring 69 then pushing the bearing 59 under the latches55 to lock them.

When starting up, the above-described device also acts as a safetymeasure against the danger of accident resulting from the freezing ofthe acceleration pedal. Indeed, since the transmission is neutralizedwhen starting up, as has been explained, there follows that freezing ofthe acceleration pedal will produce no effect and it will be possible toremedy this fault before starting.

We claim:

I. Device for neutralizing, when starting up, the driving effect of apulley having truncated checks of which a first check is secured on arotary axle whereas a seeond check is slidably mounted thereon, thecheeks being biassed by a spring tending to move the second cheek awayfrom the first one, this movement being however counteracted by agovernor mounted on the axle and of which the centrifugal masses act onthe second cheek to bring it back toward the first one as soon as theaxle starts rotating beyond a predetermined speed, the device beingcharacterized in the combination therewith comprising: a. a lockingmechanism mounted on the axle to cooperate with the second check in sucha way as to hold it in its movement toward the first cheek under theeffect of the centrifugal masses, as soon as the axle starts rotating;b. a manually operable mechanism combined with the said lockingmechanism in such a way as to release, when actuated, the second cheekwhen the axle reaches a speed of rotation greater than saidpredetermined speed, and c. wherein the locking mechanism comprises acollar interconnected with said second cheek and at least one leverpivotally mounted at one of its ends on said axle in such way that itsother end moves away from the axle under the effect of the centrifugalforce, the collar and the lever being so constructed that the said otherend of said lever comes in abutment against said collar when the axlestarts rotating and thus holds said collar, said manually operablemechanism comprising means capable of holding said lever in abutmentposition, said means being displaceable at will to release the saidlever once the axle has reached the said predetermined speed.

2. A device as claimed in claim 1 wherein the end of the said levercoming in abutment and the abutment surface of said collar are soconstructed as to allow relative sliding and facilitates release of saidcollar.

3. A device as claimed in claim 1 wherein said axle is hollow anddefines a chamber having an opening extending across the wall thereof,wherein said lever is bent in the form of a latch at its abutting end,the said latch being movable through said opening, wherein the saidmeans comprises a bearing slidably mounted within said chamber, andresilient means pressing said bearing beneath the end of said latch tohold said lever in abutment against the said collar; the said manuallyoperable mechanism further comprising a tubular elbow movable inrelation to said axle and at one end of which the said bearing issecured, a bowden cable passing through the said tubualr elbow and ofwhich one end is secured inwardly in said chamber, a control leverhaving a pivoting axis fixed with respect to said axle, the other end ofthe said cable being connected to said control lever in such a way thatpivoting of the latter in a predetermined direction forces the saidelbow and the said bearing to move inwardly of said chamber against saidresilient means to thus release said latch and allow said collar andsaid second cheek to move toward said first cheek.

4. A device according to claim 2 wherein said chamber is provided with asecond opening through the wall thereof diametrically opposite saidfirst opening, wherein a second lever identical to said first one isprovided and of which the latch thereof is movable through said secondopening.

5. A device as claimed in claim 2 wherein a second bearing is securedinside said chamber and has a fixed central portion to which the firstend of said bowden cable is secured.

1. Device for neutralizing, when starting up, the driving effect of a pulley having truncated cheeks of which a first cheek is secured on a rotary axle whereas a second cheek is slidably mounted thereon, the cheeks being biassed by a spring tending to move the second cheek away from the first one, this movement being however counteracted by a governor mounted on the axle and of which the centrifugal masses act on the second cheek to bring it back toward the first one as soon as the axle starts rotating beyond a predetermined speed, the device being characterized in the combination therewith comprising: a. a locking mechanism mounted on the axle to cooperate with the second cheek in such a way as to hold it in its movement toward the first cheek under the effect of the centrifugal masses, as soon as the axle starts rotating; b. a manually operable mechanism combined with the said locking mechanism in such a way as to release, when actuated, the second cheek when the axle reaches a speed of rotation greater than said predetermined speed, and c. wherein the locking mechanism comprises a collar intercOnnected with said second cheek and at least one lever pivotally mounted at one of its ends on said axle in such way that its other end moves away from the axle under the effect of the centrifugal force, the collar and the lever being so constructed that the said other end of said lever comes in abutment against said collar when the axle starts rotating and thus holds said collar, said manually operable mechanism comprising means capable of holding said lever in abutment position, said means being displaceable at will to release the said lever once the axle has reached the said predetermined speed.
 2. A device as claimed in claim 1 wherein the end of the said lever coming in abutment and the abutment surface of said collar are so constructed as to allow relative sliding and facilitates release of said collar.
 3. A device as claimed in claim 1 wherein said axle is hollow and defines a chamber having an opening extending across the wall thereof, wherein said lever is bent in the form of a latch at its abutting end, the said latch being movable through said opening, wherein the said means comprises a bearing slidably mounted within said chamber, and resilient means pressing said bearing beneath the end of said latch to hold said lever in abutment against the said collar; the said manually operable mechanism further comprising a tubular elbow movable in relation to said axle and at one end of which the said bearing is secured, a bowden cable passing through the said tubular elbow and of which one end is secured inwardly in said chamber, a control lever having a pivoting axis fixed with respect to said axle, the other end of the said cable being connected to said control lever in such a way that pivoting of the latter in a predetermined direction forces the said elbow and the said bearing to move inwardly of said chamber against said resilient means to thus release said latch and allow said collar and said second cheek to move toward said first cheek.
 4. A device according to claim 2 wherein said chamber is provided with a second opening through the wall thereof diametrically opposite said first opening, wherein a second lever identical to said first one is provided and of which the latch thereof is movable through said second opening.
 5. A device as claimed in claim 2 wherein a second bearing is secured inside said chamber and has a fixed central portion to which the first end of said bowden cable is secured. 